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Session 36 - Solar Activity.
Display session, Tuesday, June 11
Tripp Commons,

[36.02] On the Peculiar Radio Polarization of a Sunspot and the Distibution of the Coronal Plasma

A. Vourlidas, T. S. Bastian (NRAO), M. J. Aschwanden (UMd)

A comprehensive set of microwave, soft x-ray and magnetic observations of solar active region NOAA/USAF 7123 was obtained during 4--9 April, 1992. The observations show an unusual 4.7 GHz source which is polarized in the sense of the ordinary mode over the umbra of the leading spot. A detailed analysis of the daily radio and soft X-ray maps of the spot indicates that (i) the umbral magnetic field is strongly confined, (ii) the umbral and penumbral loops have distinct atmospheres and (iii) temperature gradients may exist both radially and vertically over the spot. A possible scenario for the temporal evolution of the spot is also presented.

Program listing for Tuesday